Method for manufacturing residual oils of high asphaltic content



Feb. 2, 1937. H. e. NEVlTT ,0

METHOD FOR MANUFACTURING RESIDUAL OILS OF HIGH ASPHALTIC CONTENT Filed June 16, 1932 LIGHT OILs T HEAVY CHARGE on.

I LIIGIHT CHARGE On.

BY W

AT'ToRNEY Patented Feb. 2, 1937 UNlTED STATES PATENT OFFICE Henry G. Nevitt, Kansas City, Mo., assignor to Socony-Vacuum Oil Company, Incorporated, New York, N. Y., a corporation of New York Application June 16, 1932, Serial No. 617,529

4 Claims.

This invention relates to the manufacture of residual hydrocarbon oils of highly asphaltic nature such as are used for binders in the construction of oiled and. asphaltic road surfaces and for other construction and manufacturing uses for which products of this type are adapted.

Specifically it relates to method and means for manufacturing the desired product from raw materials, and to method and means for separating such product where it occurs in recoverable form in residual streams from other processes which may be operated for other purposes.

Asphaltic road oils are essentially oils of an asphaltic or asphalt-like nature diluted to a greater or less degree with lighter oils of a semiasphaltic or non-asphaltic nature. The degree of dilution is that required to meet specifications as to asphalt content, viscosity, and the like. Ductility and percentage of free carbon in the residue are also frequently specified. In use, these oils fulfill varying purposes ranging from the compacting and water-proofing of dirt roads to the production, when mixed with gravel, of a high type of surface approaching bituminous concrete in nature. Due to the necessarily wide range of specifications, which arises both from range of application and from lack of precise knowledge of the meaning of specific properties, a rigorous definition of road oil can not be formulated.

To those acquainted with the art, the term asphaltic road oil has a definite meaning. This meaning is more physical than chemical, and while the range of the class is wide, it is realized within the art that materials of this class are distinctly different from ordinary fuel oil residues produced at random conditions. It is equally well realized that mere reduction of an ordinary fuel oil residue to meet specifications of penetration or of viscosity will rarely result in a road oil meeting other specifications which are equally important except by the fortuitous circumstance of the starting material having been fit for the product. The manufacture of road oils is essentially a manufacture in that proper starting materials must be selected and proper process steps carried out upon them in order that the final product shall fully meet all of the desired specifications. The mere reduction or dilution of any residue to meet one point of specification usually results in a failure to adequately meet most of the other points of specification.

As an example of the type of material at present designated as road oil, there is quoted here the ofiicial specification adopted for one type of road oil by the Highway Department of the State of Nebraska for the year 1931.

Nebraska 1931 road o'iZ specifications (Adopted April 1, 1931) No. 1 Road Oil for Sand-Hill Constr.

A. Type of oil Max.

Viscosity (Saybolt furol) 122 1 seconds- Asphalt residue of 100 penetratwn (77 F.)

percent Ductility of asphalt residue at 77 F.,

cms Flish point (Cleveland open cup), degrees Specific gravity at 77/77 F Volatilization loss (325 F., 50 gm hrs.)

per cent 4 Distillation test;

Total percent distilled up to 680 F.

(sea level) Bitumen insoluble in 86 Baum naphtha,

percent Soluble in carbon tetrachloride, percent Paraflin wax or scale, per cent Water and sediment, per cent This oil is one which has been successfully used for the purpose intended, and can be produced with ease by the method set forth in the present disclosure. The production of this material by the methods of the prior art, with which I am at present familiar, is a matter of considerable difiiculty and usually to meet some of the specifications requires that some of the others be disregarded.

Other products of the same general type which may be manufactured by the process of this invention and are within the contemplation of this invention run throughout the range from very dilute to extremely concentrated residues, many of which may be solid or semi-solid at atmospheric temperatures. All of these products, however, will show in varying degrees the physical properties characteristic of the type.

The starting material for road oil manufacture will usually be an oil containing asphaltic material, and such asphaltic material may be either of natural origin or the result of previous treatment of the oil. When the starting material is residual oil from an asphalt base or mixed base crude the asphaltic material is of natural origin. Frequently the asphaltic material has originated as a result of some prior treatment of the oil.- For instance the oil may have been oxidized or treated with sulphur with the definite aim of producing asphalt-like material. Also, the asphaltic duced to the desired consistency. An alternate 1 method is to heat'the starting material in a pipe coil heater and flash to the required residue. Either of these methods requires a reheating which is not only in itself costly, but which is more or less incapable of that rigid control which is necessary to avoid side reactions resulting in the reduction of viscosity of the desired residue or formation of free carbon, both of which are detrimental to the product.

Materials of an asphaltic nature are present in the residual oils of most commercial cracking systems. As a usual case, the usefulness of these oils is decreaseddue to the manner in which they are separated, from the process. A prolonged exposure to the heat and pressure conditions of cracking results in decompo'sition with alteration of the viscosity and ductilityusually associated with a given specific gravity, and in an increase in free carbon insoluble in the usual test solvents. In consequence of this the ordinary residual oils from cracking operations are usually very far from the characteristics'required in good road oils. 7

I have found that by the process of my invention as herein disclosed I may separate the asphaltic residual oils, no matter from what source, in such a manner as to preventtheir decomposition and preserve in them'all of the inherent characteristics of the starting stock which would tend to make a good road oil; I have also found that this process enables me to operate in connection with processes which produce an asphaltic residue, but normally decompose it or contaminate it,

in sucha manner as to-Tescue the asphaltic material from the system with a minimum of decomposition or contamination; I have thus been able to avail myself of a considerably wider source for the production of road oils of superior quality than is at present known to the industry.

I have also found that the process of this invention, when operated in conjunction with other processes. such as cracking processes, enables me to separate the asphaltic oils in a manner which 7 does not in any way interfere with the proper operation of the system from which'they originate for its principal purpose. Also, by the process of the invention I am enabled to separate the operation of parting the asphaltic materials from the system from the operation of generating the asphaltic materials so that each step in the operation may be operated with a maximum of eificiency. r

This invention has for an object the provision of a method for separately controlling the production conditions for the asphaltic material and the final specifications of the finished product in, order that one may be varied as desired without materially aifecting the other. 1

A further object is theprovision of apparatus in which the process of the invention may be carried out..-

:A further object of this invention is that of enabling the adaption of existing processes for crackingv and/or synthesizing gasoline in .such manne'rthat their residual oils may be so separated as to yield an asphaltic oil of desirable characteristics.

Among the objects of this invention are those of controlling the chemical characteristics of the product, controlling the physical characteristics of the product, controlling the character of the stock from which the product is synthesized or segregated and such further objects as may hereinafter appear. 7

the stock which is returned in such manner that both the problem of meeting specifications of product and the problem of best operation of the originating system are commercially met. 5

In order'that" the method and apparatus by which my invention is practised may be more thoroughly understood, reference is made to the drawing attached to and made a part of this speci- V fication.

Figure 1 illustrates in diagrammatic form the application of my invention to cracking processes where cracking is completed within the heating,

coil followed by vaporization and separation. The vaporizer of the cracking system in this case may be fitted to carry out my invention without in any way disturbing its normal function as anin tegral portion of the cracking system. Figure 1 may also be considered to set forth a system which can be used primarily for the p-roductionrof asphaltic residue with cracking as an incidental thereto, as hereinafter explained.

Figure 2'illustrates an apparatus which has been successfully used in the practice of the invention.

Referring more specifically to Figure 2, A is a vaporizing chamber shown in section in order that internal arrangements may be made clear. This vaporizing chamber may or may not be fitted in its upper portions with baflles, mistcatching devices, or bubble trays, the presence or absence ofthese being more or less optional as required by the process in conjunction with which this vaporizer is operated. However, it is intended that the function of the body ,A should be basically that of a Vaporizer and any fractionation as by extensive use of bubble trays, etc., should not be considered a portion of the duty of this body A and except as necessary for. the removal of mist, etc., return to the liquid in the bottom of body A of any material condensed in the upper portion preferably should not be prac- Entering the side of 'the vaporizer A at a point spaced above its bottom is a pipe I equipped with a valve. The purpose of this pipeis to introduce into the vaporizer the stream of products to be vaporized andseparated therein. The valve upon this line may be merely for thepurpose of cutoff or it may be, required by the sys-' tem in which the vaporizer is operated as a controller valve of that system That is to say, the V valve is not a'necessary feature'ofpipefl; At the top of the vaporizer A vapors areallowed to pass At the bottom of the va- 4. The level of this liquid is maintained at some point such as 5, by automatic or manual control of a valve placed in line 4. Line 3 enters the v side of the vaporizer and discharges at some point between line I and liquid level 5 through a spray device as indicated, or if preferred, it may discharge below liquid level 5 in the bottom of In operation the function of this line 3 is to introduce into the vaporizer A an oil the liquid.

Figure l, A is the vaporizer as before and I, 2,

3, 4 and 5 have the same meaning as before expressed. B is a bubble tower, C a furnace and D a pump. This system illustrates the use of my invention in connection with cracking proc esses wherein the reaction is complete within the heating coils. In this process the pump D, taking suction from the bottom of the bubble tower B, passes the oil through coils in furnace C. Such oil may or may not be under pressure in excess of that required to overcome flow resistance.

In case back pressure is held upon the heating coil, it may be released through the valve in Entering vaporizer A the reaction stream from line I, consisting of cracked products, uncracked and unpolymerized gas oil, partially polymerized gas oil, and polymerized residue separates, the polymerized residue falling to the bottom to be removed to storage and the cracked product, unconverted gas oil and partially polymerized gas oil pass through vapor line 2 to bubble tower B. In this bubble tower the portions heavier than the cracked products are condensed to be collected in the bottom and returned to the furnace by pump D.

-The cracked products'pass over-head from the bubble tower to be condensed and taken to storage. Charge for the system is introduced from a storage tank into the bubble tower. Gas oil taken from a storage tank is discharged into vaporizer A through line 3 and the asphaltic residue product is withdrawn through line 4. In the operation of this system, the temperature of vaporizer A at and above the entrance of line I is so controlled that partiallly polymerized products of the reaction stream remain as vapors and only such products of the reaction stream as are of satisfactory nature remain unvaporized to collect in the storage below liquid level 5. To check further evaporation from and/or change in this product in the short time interval that must elapse before it can be withdrawn the coo-ling effect of oil from line 3 is taken advantage of. It may also be the case that some portion of the oil fromline 3 remains unvaporized to join with the asphaltic residue and it is in the inter-relation of the temperatures at the entrance level of line I and below liquid level 5 as controlled by the amount of oil introduced through line 3 that the final characteristics of the product withdrawn through line 4 are controlled. 7

In another sense the apparatus of Figure 1 may be-considered as a method for making as' phalt residue rather-than as a method for making a cracked product of the nature of gasoline. That is to say, the system of Figure l, of which vaporizer A is a part, is of such a nature that its operation in the methoddescribed above but with variations in the stock primarily charged, time relation of various elements; etc., could be operated for the production of an asphalt residue with the production of gasoline-like hydrocar-'-- bons incidental thereto.

It is understood as the sense of above'dlscus' separate from the reaction stream the heavy product formed therein. It is also to be understood that the process of this invention, insofar as it relates to the operation carried out in vapor- I izer A, as shown and explained in Figure 2 may be carried out for the separation of asphaltic residual oil from a heated stream containing such asphaltio residue, regardless of its source. That is to say, the material entering the vaporizer may be the finished reactionstream of any process designed to'alter oils originally non-asphaltic to an asphaltic nature; it may be the residue portion of an asphaltic crude which has been subjected to topping and is desired to be furthertopped in the vaporizing body of this invention; or it may be a stream of residual oil from any commercial cracking process, introduced to the vaporizer of this invention in order to separate from it asphaltic residual oil in the manner disclosed.

In the present process, if the apparatus of Figure 1 be used and the conditions chosen be such that the process of the main apparatus is that of cracking an oil to produce gasoline, the following discussion will be applicable; as in most cracking processes, the residual oil contains bodies of an asphaltic nature.

The reaction stream entering through line I will have a temperature in the vicinity of 900 Fahrenheit and will consist of cracked gasoline product, uncracked gas oil, and products ,containing varying amounts of asphalt or asphaltlike substances. Of these last, I prefer to retain only the heavier in liquid form, as they are of higher asphalt content. The others I desire to remain in the vapor state, both that I may retreat them for the further production of asphaltic material and gasoline, and that they may not diit is desirable that the base residue be relieved of the influence of heat immediately.

It would be theoretically suflicientprobably, to remove it immediately from its heated surroundings. Practically, this removal would be uncertain and at best would introduce a complication of apparatus.

I prefer to cool it by spraying upon its surface; or introducing below its surface a 1 stream of oil from pipe 3. This oil may be heated partially or almost to its vaporization point, or it may be cold. Its heat content and amount are so adjusted that upon entering the vaporizer, it vaporizes and in picking up latent heat of Vaporization cools the residueor base oil to a de- 1 gree sufficientto prevent its continuing reaction wlthldepositionbf carbon, etc. In cooling by heavy and viscous to meet specifications, as is usually the case, the amount of coolant can beso proportioned, or its properties can be so selected that a suflicient portion of it remains unvaporized and is'hotblended with the base. Herein lies an important advantage of the process of my inven tion.- The process which is producing the asphaltic residue, if its principal object is production ofthat residue,'may be so adjusted as to get the maximum efliciency of yield and quality E'of base product. Then the alteration of the product to meet varying specifications can be conducted at'will without affecting the adjustment of the process step where the product originates. If the process which is producing'the asphaltic Eresidue is a cracking operation; the desirable product may be separated and altered to meet specifications without impairing the maximum efiiciency of the cracking process.

Afurther desirability of the process of my invention appears from consideration of the chemical theory at present believed to cover the facts. The reaction stream entering through line fl consists of light gasoline-like hydrocarbons (present in varying quantity depending on Whether or not the preceding process is one of cracking), unconverted gas oils, products partially polymerized to an asphaltic nature, and products polymerized sufficiently that they may be removed as asphaltic product.

vaporization at high temperature, that is,without substantial extraction of heat, will render all except the lastnamed vapor, leaving the desirable polymerized product as liquid. This product may betoo heavy to meet physical specifications as to viscosity, etc., and must be cooled to'avoid its further reaction which may result in formation of undesirable free carbon, loss of viscosity; etc. Virgin gas oil is admitted through line 3 and in vaporizing accomplishes the desired cooling. -The amount of gas oil so introduced and/or the temperature to which it is heated beforeintro duction, in relation with the temperature of the vaporizer, governs the amount which may remain unvaporized to dilute the base oil to specification. In this way the lighter oils which are already partially polymerized are retained within the conversion cycle, with a resulting increase in efiiciencyfor that cycle, and their place, insofar as their dilution function is concerned, is taken by virgin gas oil of similar physical characteristics, but of different chemical structure; The relationship between virgin gas oil hydrocarbons and partially polymerized hydrocarbons is such that for the same boiling point the partially polymerized product has a higher specific gravity and viscosity, and thus, solely by an operation broadly directed to'heat regulation, the quality of prod- Y uct may actually be improved.

general statement'of temperatures, etc., would be of small value, due both to the varying character- 'istics of the process which is the source of the material entering through line I, and tothe broadness of the range of specifications which -may be met by the material departing through 3i=fications with no greater difficulty than is ordi- It is obviousto those skilled in the art that a line 4. With a given system or source of material and a given set of specifications to be met, it is For instance, the product coming through the transfer line contains a certain percentage of asphalt capable of being separated as a product and has a certain temperature. .The percentage of asphalt, as well as its characteristics, tends to vary greatly with the characteristics of the charging stock and cannot be predicted from anysimple tests of the stock or deductions therefrom. A typical case would be an average mixed stock from a refinery operating on Mid Continent crude. At moderate pressures, if the transfer stream were not quenched the vaporizer top temperature would be about 780 F., the vaporizer bottom or liquid temperature would be about 760, and the bottom product would be unfit for road oil of satisfactory quality. By introducing a quenching oil in the tower and reducing the bottom vaporizer or liquid temperature to prefer ably from 650 to 700 F., which can be done without materially affecting the vaporizing andother primary function operations of the unit, or giving an operation from such standpoint materially different from the first, I can produce a bottom product which has the following characteristics and is a desirable asphaltic product of its type.

Specificgravitn- -Above 1.00, say 1.05 in typical case.

Asphaltic co ntent.Can be varied to suit by in typical case.

Insoluble in 86 paraflin naphthm-Relatively high--say 18% in typical case. 7

Similarly with other tests, which will show a very high quality product of its type, which cannot otherwise be. made on this equipment from ordinary charging stocks without appreciably affecting the primary operation.

The quantity of quenching oil "required in the bottom of the evaporator to reduce the tempera-- ture to the point in the range specified as determined by the requirements of the particular operation (or to not quite this range at some loss or risks of loss in quality characteristics in the road oil produced) evidently depends upon the proportion of road oil produced by the charging stock and upon the thermal characteristics of the quenching stock. The quantity can be calculated from the heat requirements of the cooling operation and the heat intake of the quenching stock when raised to the tower conditions. advantage of my invention is the'fiexibility of this control, as small amounts of volatile quenching stock producing considerable cooling efiect by vaporization, or larger amounts of less volatile quenching stock may be used to get the same thermal results. The choice will be dictated by oper- One" ating conditions of theunit, degree of reduction or other physical characteristics of the road oil produced due to the admixture of the non-volatilized portion of the quenching stock toit, or

other, manufacturing reasons. r

In the typical case referred to the per cent of used would be about 7 or 8% of the charge using the gas oil charge as quenching stock to cool the bottoms to around 660 F.

It may be seen that by the process of my invention I may produce oils of asphaltic nature under the conditions best suited for their manufacture, may separate from the stream only base oil of a desired nature, and return insufficiently treated oils to process; then, as a separately controlled step, I may bring about the dilution of the asphaltic material to a desired degree without in any way disturbing the conditions which I have found best for the production of the base oil.

Throughout this specification and in the following claims the terms asphaltic and polymerized have been used. These terms are here used in the general sense in which those terms are at present used in this branch of the industry. As this usage is considerably more loose and not specifically parallel to the general chemical significance of the terms the following explanatory definitions are made.

In the following claims where mention is made of completely polymerized oil it is intended that this term or its equivalent shall cover oil whose asphaltic content or asphalt-like nature is such that it may be withdrawn from the system as a desirable end product. Where partially polymerized oil is used, it is intended that this term or its equivalent shall cover oil whose nature is similar to the desired product yet which is not sufiiciently so as to make it a desired end product, and which may be further altered to approach or become the desired end product.

It is also understood that the terms asphaltic and asphalt-like shall be synonymous in the interpretation of the claims and shall indicate an oil whose physical characteristics are of the kind generally understood as covered by the term asphaltic or meeting specifications of the kind noted, or capable of simple dilution or reduction to so meet them, regardless of actual chemical structure.

I claim:

1. That process of producing residual oil of high asphaltic content and low carbon content which comprises flowing a heated stream of oil containing an asphaltic residue into a vaporizing chamber, allowing vaporization under conditions of temperature and pressure not conducive to gasoline formation but capable of detrimental conversion of the asphaltic material to separate from that stream all products lighter than an asphaltic residue which contains 60-70 percent or more of penetration asphalt, which has less than 1 percent of residue insoluble in carbon bisulphide, and which possesses physical properties suitable for road making material, cooling the said asphaltic residue to check further molecular structural change thereof, said cooling being accomplished by introducing to the vaporizer an oil which is substantially vaporizable at temperatures below that of the first vaporization, at a point without the main path of flow of vapors from said first vaporization, allowing said second oil to vaporize in contact with the residue from said first vaporization, and thereafter removing said asphaltic residue from the vaporizer.

2. That process of treating a heated stream of oil containing asphaltic material which comprises separating from it by vaporization under conditions of temperature and pressure not conducive to gasoline formation but capable of detrimental conversion of asphaltic materials a heavy asphaltic residue, cooling the said residue to check further molecular structural change thereof by introducing to the vaporizer a second oil, said second oil vaporizing to a predetermined extent upon contact with said residue and prior to said contact having been protected from substantial contact with vapors from the first vaporization, and diluting the said residue with a selected unvaporized residue from said second oil to produce a combined residual oil containing at least 60-70 percent of 100 penetration asphalt, a carbon bisulphide insoluble portion of the order of 1 percent and possessing physical properties suitable for road making material.

3. That process of producing asphaltic residual oil which comprises establishing a stream of heated oil, a portion of which consists of partially polymerized oil and a further portion of which consists of completely polymerized oil, vaporizing said stream at such pressure and temperature that said completely polymerized oil remains liquid, all other portions including said partially polymerized oil being vaporous, said temperature and pressure being insufficiently high to cause gasoline formation but high enough to cause detrimental decomposition of said residue if continued, reducing the temperature of said residue to avoid such decomposition by introducing to the vaporizer a second oil, capable of being substantially completely vaporized at the temperature of said first vaporization, protecting said second oil from substantial contact with the vapors of said first vaporization, allowing said second oil to vaporize while in contact with said residue, admixing and simultaneously removing vapors from both vaporizations, and removing as a residue an oil sufficiently polymerized to have at least 6070 per cent of 100 penetration asphalt and a relatively low content of material insoluble in carbon bisulphide.

4. That process of producing asphaltic residual oil which comprises establishing a stream of heated oil, a portion of which consists of partially polymerized oil and a further portion of which consists of completely polymerized oil, vaporizing said stream at such pressure and temperature that said completely polymerized oil remains liquid, all other portions including said partially polymerized oil being vaporous, said temperature and pressure being insufliciently high to cause gasoline formation but high enough to cause detrimental decomposition of said residue if continued, reducing the temperature of said residue to avoid such decomposition by introducing to the vaporizer a second oil, capable of being substantially vaporized at the temperature of said first vaporization, protecting said second oil from substantial contact with the vapors of said first vaporization, allowing said second oil to vaporize while in contact with said residue, admixing and simultaneously removing vapors from both vaporizations, diluting said residue with a predetermined unvaporized portion of said second oil, and removing as a residue an oil having at least 60-70 percent of 100 penetration asphalt and low in content of material insoluble in carbon bisulphide.

HENRY G. NEVI'I'I. 

